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  • Development and Empirical Research of Mobile Short Video APP User Experience Scale Based on Perceived Affordance

    Subjects: Library Science,Information Science >> Library Science submitted time 2024-04-17

    Abstract: Purpose/Significance Developing a user experience scale for mobile short video APP, and provide reliable suggestions for the version update iteration of mobile short video APP. Method/Process Based on the theory of perceived affordance, a qualitative scale was constructed according to the results of literature research and group discussion. The scale was quantitatively optimized through pre-investigation, and data were obtained through formal investigation. Exploratory factor analysis and confirmatory factor analysis were carried out on the effective data, and the formal scale was revised and formed. Result/Conclusion The formal scale includes five main dimensions, 10 sub-dimensions and 30 items of perceived physical affordance, perceived cognitive affordance, perceived emotional affordance, perceived control affordance and perceived participation affordance, and uses the formal scale to measure the user experience level of mobile short video APP.

  • Spatiotemporal variation characteristics and influencing factors of heat wave and precipitation deficit flash drought in the Loess Plateau

    Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-04-07 Cooperative journals: 《干旱区地理》

    Abstract: Flash drought is a type of drought characterized by rapid intensification. In the context of global warming, flash droughts are increasingly frequent, which has had a devastating impact on the agricultural ecosystem and public health of China. Understanding the spatiotemporal variation characteristics and influencing factors of flash drought events is of critical importance for monitoring, early warning, and loss prevention. On the basis of ERA5- Land data from 1981 to 2020, this study examined the spatiotemporal variation of two types of flash drought (heat wave and precipitation deficit flash drought) in the Loess Plateau using trend and correlation analyses. The relationship between the different atmosphere-ocean oscillation indices and the number of flash drought is also examined. The following results are presented. (1) The frequency of the two types of flash drought increased significantly from 1981 to 2020, with a higher increasing precipitation deficit rate [0.54 penta·(10a) − 1 ] than that of heat wave [0.46 penta·(10a)−1 ] flash drought. Particularly, the two types of flash drought had a similar pattern in decadal variation. Before 1998, the two types of flash drought primarily displayed low fluctuation. From 1998 to 2010, the number of flash droughts rapidly increased. The growth rate of flash droughts stalled and began to decline after 2010. (2) A spatially significant (P<0.05) upward trend for heat wave (precipitation deficit) flash drought was observed in 36.5% (37.5% ) of the Loess Plateau. The parts of the Loess Plateau with gullies and hills, as well as the eastern Hetao Plain and the Fenwei River Valley Plain, had a marked increase in the incidence of heat waves and precipitation deficit flash droughts. (3) Considering the influencing factors, the trend and interannual oscillations of flash drought in the Loess Plateau can be explained by the sea surface temperature (SST) anomaly in the NINO B region and the atmospheric pressure anomaly in the northern Qinghai-Tibet Plateau. The Loess Plateau had an increase in the probability of flash drought due to positive air pressure anomalies in the northern Qinghai-Tibet Plateau and large SST anomalies in the central equatorial India Ocean.

  • 基于MF-DFA的西安昼夜复合高温事件 变化特征及影响因素

    Subjects: Geosciences >> Atmospheric Sciences submitted time 2022-01-21 Cooperative journals: 《干旱区地理》

    Abstract:采用随机重排去趋势波动分析(MF-DFA)和极点对称模态分解法(ESMD),对19552019年西安市昼夜复合高温事件变化特征进行分析。结果表明:(1)气象站点迁移,造成对西安市极端高温变化趋势低估。其中,最高温原始数据与订正序列阈值相同;订正后,最低温阈值相对偏低0.2~0.5 ℃。(2)MF-DFA、90.0%和95.0%阈值方案识别高温事件年代变化具有相似性,而99.0%阈值和相对阈值方案是结论不确定性的主要来源。(3)在变化特征上,西安市昼夜复合高温事件兼顾3.3~3.8 a年际波动和趋势变化,20世纪80年代中期,昼夜复合高温天数呈现显著增多。(4)赤道西太平洋海温异常,可作为西安市昼夜复合高温预警的关键海区。即赤道西太平洋海温异常偏高时,往往对应西安市昼夜复合高温多发期,并指出南亚高压偏北、西太平洋副热带高压西伸,是影响西安市持续昼夜复合高温的环流机制。

  • 秦岭南北潜在蒸发与气温响应关系及其影响因素

    Subjects: Geosciences >> Atmospheric Sciences submitted time 2021-02-13 Cooperative journals: 《干旱区地理》

    Abstract: 蒸发是水文循环的重要组成部分,精细化蒸发变化与气象要素的响应关系,对中国重要生 态过渡带水资源、生态恢复重建以及社会经济的可持续发展具有重要意义。基于 1970—2017 年 70 个气象站点观测数据,辅以趋势分析和小波相干方法,对秦岭南北气温和潜在蒸发(ET0)变化特征 进行分析,探讨气象要素与 ET0 的响应关系。结果表明:以滑动相关方法为基础,无论是滑动窗口 调整,还是去趋势序列,气温与 ET0 均呈现正相关关系,说明秦岭南北气温上升,ET0 增加;但是,秦 岭南北气温与 ET0 相关关系存在时空差异。以 1993 年为时间节点,前期气温和 ET0 相关性呈现增 加趋势,后期则逐渐减弱;空间上西秦岭地区是气温和 ET0 的弱相关区。在主导因素上,ET0 对太阳 辐射变化更为敏感,风速并非区域 ET0 变化的主导因素,从而导致“蒸发悖论”现象并不突出。多因 素主导 ET0 变化,是秦岭南北 ET0 与气温响应关系存在时空差异的原因。